Malnutrition is a major issue in developing countries with long-term implications for economic development. Agricultural diversification has been recognized as a strategy to improve nutrition and human health, and a risk coping strategy in the face of climate change. We use the 2008-2010 Tanzania National Panel Survey, which includes about 3,700 children, to investigate the effect of crop diversification on child health. We use an instrumental variable approach and estimate the effect of crop diversification on child growth by controlling for unobserved heterogeneity. We show that crop diversification has a positive and significant impact on long-term child nutritional status.